A conventional type of rotary pump used for an automobile is driven by an automotive engine or an electric motor. If the rotary pump is driven by the engine, the pump cannot work before the engine starts. On the other hand, if the rotary pump is driven by an electric motor, that electric motor is required to have enough power to turn the pump and such an electric motor consumes a large quantity of energy, if the electric motor rotates the rotary pump during all of the time the automotive engine is operating.